Bad news travelers, you can’t count on your flight to take off and arrive on time. Delays and cancellations happen, perhaps more frequently than you might expect. In fact, according to DOT statistics, in a one-year span, more than 20 percent of flights didn’t arrive on time.

Perhaps the most frustrating experiences occur when there are mass delays and cancellations. They come from snowstorms, hurricanes or computer outages. And when trouble starts, flights get canceled, then subsequent flights get delayed and soon thousands of travelers are stranded.

Don’t get stuck in the herd. Know Before You Go! Here’s what you need to do get your travel back on track amid mass delays.